Can you sex my Silkie Bantam chicks?

So its been six weeks or so since my two chicks hatched. They have grown a lot since then, here they are when they hatched:-

And here they are now.

This is "Buffy", you can see from the lovely crest which of the two this is:-

And the other is called "McNuggets" (LOL), a poor scrappy looking thing with a patchy neck, quite a large comb for its age and wattle:-

As you can see, these chickens are completely different in appearance. So what do I have here? Initially I thought Buffy with her fine crest was male, but as times gone on I feel "she" is a hen. What do you think?

Buffy is likely a pullet; McNuggets a cockerel. I say this simply because he has larger wattles than Buffy. It is difficult to sex chickens at this young age, but that would be my best guess. They're such pretty silkies!